B= \(\dfrac{1}{4}\)+\(\dfrac{1}{12}\)+\(\dfrac{1}{24}\)+....+\(\dfrac{1}{79600}\)
C= \(\dfrac{2}{5}\)+\(\dfrac{2}{45}\)+\(\dfrac{2}{117}\)+....+\(\dfrac{2}{6885}\)
Trình bày đầy đủ cả phép tính nha
Tks:3
B= \(\dfrac{1}{4}\)+\(\dfrac{1}{12}\)+\(\dfrac{1}{24}\)+....+\(\dfrac{1}{79600}\)
Bài 3: (Đề 2) Tìm y
a) \(2\dfrac{2}{5}:\) y x \(1\dfrac{3}{4}=\dfrac{7}{8}\) b)\(3\dfrac{2}{5}:y:1\dfrac{1}{4}=2\dfrac{3}{5}\) c) \(\dfrac{12}{5}-2\dfrac{2}{5}x\) y \(=1\dfrac{1}{4}\)
Tìm x:
\(\dfrac{3}{5}\) : x = \(\dfrac{1}{3}+\dfrac{1}{2}\) x : \(\dfrac{7}{12}\) = 2 x - \(\dfrac{3}{2}\) = \(\dfrac{11}{4}-\dfrac{5}{4}\) x + \(\dfrac{5}{4}\) = \(\dfrac{3}{2}+\dfrac{7}{12}\)
Tìm y
\(\dfrac{2}{5}\) X y : \(\dfrac{7}{4}=\dfrac{7}{8}\)
2\(\dfrac{2}{5}\) : y x 1\(\dfrac{1}{4}\) = 2\(\dfrac{3}{5}\)
\(\dfrac{12}{5}-1\dfrac{2}{5}x\) y = 1\(\dfrac{1}{4}\)
\(\dfrac{2}{5}\)*\(15\dfrac{1}{3}\)-\(\dfrac{2}{5}\)*\(10\dfrac{1}{3}\)
\(12\dfrac{5}{11}\)-(\(3\dfrac{1}{4}\)+\(2\dfrac{5}{11}\)]
\(\dfrac{34}{31}\)-\(\dfrac{19}{28}\)-\(\dfrac{3}{31}\)
Tìm x:
a) x +\(\dfrac{4}{15}\) = \(\dfrac{4}{12}\) b) x - \(\dfrac{5}{8}\) = \(1\dfrac{2}{3}\)
Thực hiện phép tính-tính nhanh giá trị biểu thức
A=19\(\dfrac{1}{4}\) + \(\dfrac{1}{2}\)x 2\(\dfrac{1}{3}\)+5,75 - \(\dfrac{1}{6}\)+74
B=[(\(\dfrac{1}{3}+\dfrac{1}{4}\))] x \(\dfrac{12}{19}+\dfrac{12}{19}\)] : \(\dfrac{4}{5}-\dfrac{1}{4}+2012\)
C=\(\dfrac{232323}{353535}:\dfrac{76x47-28}{76x46+48}\)
a) \(\dfrac{3}{10}\)x\(\dfrac{4}{2}\)x\(\dfrac{5}{6}\) b) \(\dfrac{6}{4}\)x\(\dfrac{8}{12}\)x\(\dfrac{12}{8}\)x\(\dfrac{16}{6}\)
cái này là tính bằng cách tiện nhất nha mấy thím cứu con với